Transcript Unit VI Anatomy and Physiology of Plants and Animals

Classification of Animals
Characteristics
Common To All Animals Animal Innovations
Tissue Layers Symmetry Body Cavities Developmental Patterns Animal Classification
Parazoa Eumetazoans
Cnidarians Ctenophores Protostomes
Platyhelminthes Rotifera Nemertea Mollusca Annelida Nemotoda Arthropoda Deuterostomes
Echinodermata Phyum Chordata
Characteristics Invertebrate Chordates Vertebrate Chordates
Agnathans Jawed Fishes Amphibians Amniotes -
Unit III
Anatomy and Physiology of
Animals
Learning Goal 1
Identify the major classification
schemes of the kingdom Animalia
Characteristics
Common to Animals
Multicellular
Eukaryotic
No cell walls
Heterotrophic
Generally motile
Animal Innovations
• Tissues and Tissue Layers
As embryos of most animals
develop they form cell layers.
The inner layer called the
endoderm becomes the lining
of the gut and other organs,
The outer ectoderm forms the
external covering and nervous
system.
Between is the mesoderm
which becomes the muscles
and other structures between
the gut and the external
covering.
• Radial or Bilateral Symmetry
Animals that exhibit radial
symmetry have body parts
arranged around a central axis.
This includes two phyla,
Cnidaria ( hydras, jellyfishes,
and sea anemones) and
Ctenophora (comb jellies)
All other animal phyla have
bilateral symmetry in which a
cut along the midline from
head to tail would divide them
into mirror images.
• Body Cavities
Acoelomate – animals without
a body cavity. Have a
continuous mass of tissue
between the gut and the body
wall. Includes phylum
Platyhelmenthes (flatworms).
Pseudocoelomate- animals
with a fluid or organ filled
space between the gut and the
body wall. Includes phyla
Nemotoda (round worms) and
Rotifera.
Coelomates – animals with a
true coelom, a fluid-filled body
cavity lined by a peritoneum.
•
•
Developmental Patterns
Protostomes
Includes most invertebrate phyla.
As the zygote (fertilized egg) divides
by mitosis it exhibits a pattern of spiral
cleavage.
Cleavage is determinate, meaning that
each cell’s development is determined
as the cell is produced. In other words
it won’t develop on its own.
Deuterstomes
Includes some invertebrates and all
vertebrate phyla.
Embryos exhibit radial cleavage.
Early cells of the embryo have
indeterminate cleavage where an
isolated cell can develop into a
functional embryo
Animal Classification
•
Parazoa
Includes only one group, the
sponges.
Phylum Porifera
Lack true tissues with simple body
plans.
Filters food particles from
surrounding water in a central
chamber.
Most are hermaphroditic with
individuals producing both sperm
and eggs.
Zygotes develop into flagellated
larvae that attach to substrates
becoming sessile adults.
Eumetazoans
•
Cnidarians
8900 species, nearly all of which
live in the sea.
Exhibit radial symmetry with a
body plan organized around a
saclike gastrovascular cavity.
The mouth is ringed with tentacles
for food gathering.
May exhibit a polyp or a medusa
body structure or alternate
between both.
Major groups include the hydrozoa
(hydra), Scyphozoa (jelly fishes),
Cubozoa (box jelly fish), and
Anthozoa (corals and sea
anemones).
All have nematocysts which are
encapsulated coiled threads
containing toxins that can paralyze
small prey.
• Ctenophores (comb
jellies)
Exhibit radial
symmetry.
Lack nematocysts.
Usually transparent
and sometimes
luminescent.
Live primarily in
coastal regions.
Protostomes
• Phylum
Platyhelminthes
(flatworms)
13,000 species live in
aquatic or moist terrestrial
environments.
They are acoelomate with
no respiratory or
circulatory system.
Includes turbellarians,
trematodes (flukes),
monogenoids, and
cestodes (tape worms)
• Phylum Rotifera
Microscopic, freshwater
organisms.
Well-developed digestive,
reproductive, excretory,
and nervous systems.
They are
pseudocoelomates.
Have a wheel-like corona
lined with cilia to help
them move and eat.
• Phylum Nemertea
Also known as ribbon
worms.
Mostly marine species
from 1cm to 30 meters in
length.
Have complete digestive
and circulatory systems,
with a mucous covered
proboscis to catch prey.
• Phylum Mollusca
Contain a visceral mass
enclosed in a shell with a
muscular head-foot for
locomotion.
Have a true coelom.
Mostly marine, but some
freshwater,and terrestrial.
Contain the groups
polyplacophora (chitons),
gastropods (snails and slugs),
bivalves ( clams, mussels),
and cephalopods
(octopuses, squids, and
nautiluses)
• Phylum Annelida
Habitats are marine,
freshwater, and terrestrial.
Highly segmented body
divided into repeating units.
Digestive and circulatory
systems run the length of the
body.
Contain groups, polychaeta
(bristle worms), oligochaeta
(earthworms), and hirudinea
(leeches)
• Phylum Nematoda
(roundworms)
80,000 described species, but
estimated that more than half a
million exist.
Many are microscopic, but can
be a meter or more long.
Have ecological, agricultural,
and medical significance.
Major decomposers, can be
parasitic on crop plants and
people.
• Phylum Arthropoda
Have segmented bodies
with as rigid exoskeleton.
Body segments consist of
the head, thorax, and
abdomen.
Consist of subphyla
chelicerata (spiders,
ticks, mites, and
scorpions), crustacea
(shrimp, lobster, crab),
myriapoda (centipedes,
and millipedes), and
hexapoda (insects)
Deuterostomes
• Phylum Echinodermata
6600 species of sea
stars, sea urchins and
others.
Have a well-developed
coelom.
Exhibit radial symmetry
as adults, with no head or
central brain.
Phylum Chordata
Characteristics
Have a notochord, a flexible rod consisting of
fluid-filled cells surrounded by tough connective
tissue.
Have a segmental body wall and tail muscles.
Contain a dorsal hollow nerve chord with a
brain-like structure at the anterior end.
Have a perforated pharynx at some stage of
development.
Invertebrate Chordates
• Subphylum Urochordata
(tunacates or sea squirts)
Water pulled in through an
incurrent siphon with a mucous
net to trap particulate food.
• Subphylum
Cephalochordata (lancelets)
Have sense organs on
tentacles that grow from an
oral hood.
Occupy shallow marine
habitats.
Vertebrate Chordates
• Agnathans (Jawless Fishes)
Phyla Myxinoidea (hagfishes)
and Peteroyzontoidea
(lampreys).
Lack jaws, and have skeletons
conposed of cartilage.
Hagfishes are scavengers in
marine environments and most
lampreys are parasites as
adults.
Jawed Fishes
Chondrichthyes
Skates, rays, and
sharks
Have cartilagenous
skeletons
Use electroreceptors
to detect weak
electric currents
produced by other
animals.
Bony Fishes
• Fishes with bony
endoskeletons.
Have a gas-filled swim bladder
to increase buoyancy.
• Actinopterygii
Most primative are sturgeons
and paddlefishes
Teleosts are the most diverse
and successful group of bony
fishes.
• Sarcopterygii (lobe-finned
and lungfish)
Amphibians
• Carnivorous as adults, but
aquatic larvae may be
herbivores.
• Have thin, scaleless skin that
must remain moist to help with
gas exchange.
• Many have life cycles that
consist of both larval and adult
stages.
• Three major groups:
Anura (frogs and toads)
Urodela (salamanders)
Gymnophiona (caecelian)
Amniotes
• Characteristics
Tough dry skin filled with
keratin and lipids.
Reptiles and birds produce an
amniotic egg able to survive on
dry land. Consists of a shell,
four membranes for gas
exchange, a yolk and albumin
for nutrients and water.
Mammal embryos have the
same four membranes, but no
shell and implant in the wall of
the female’s uterus to obtain
nutrients and oxygen.
Testudines: Turtles
• Have the characteristic
bony shell consisting or a
dorsal carapace and a
ventral plastron.
• Ribs are fused to the
inside of the carapace
• Live in terrestrial,
freshwater, and marine
habitats.
• No teeth, but have a
keratinized beak.
• Sphenodontids (tuatara)
Only two surviving
species that live on
islands off New Zealand’s
coast.
• Squamata (lizards and
snakes)
Skin of keratinized scales
that sheds as animal
grows.
Regulate body
temperature behaviorally.
• Crocodilians
Aquatic predators on
other vertebrates.
Have a fourchambered heart and
care for their young
more like birds than
other reptiles.
Aves: Birds
• Have light weight, strong
skeletons with hollow limb
bones.
• Possess a keeled
sternum (breastbone) to
which flight muscles
attach.
• Have feathers which
provide aide in flight and
form an insulating cover.
• Have a high rate of
metabolism and maintain
a high constant body
temperature.
Mammals
• Four Key Adaptations
High metabolic rate and body
temperature.
Specialized teeth and jaws.
High degree of parental care.
Larger more complex brains.
• Mammal Groups:
Monotremes (egg layers)
Marsupials (pouched
mammals)
Placentals (young develop in
a placenta)
LG 1 Terms
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10.
Ectoderm –
Mesoderm –
Endoderm Radial vs Bilateral Symmetry –
Coelomate –
Acoelomate –
Pseudocoelomate –
Notochord –
Protostome –
Deuterostome –